K & N filter
Why do you think a K & N filter will set a lean code P0171?? There are many reasons for this code, faulty O2 sensor, intake leak, ECT issue, fuel pressure low and so on.
Cars & Trucks - Jeep - Grand Cherokee - 1996 Jeep Grand Cherokee
Answers & Comments
I don't know if you guys are still on this topic but all cars can have issues with the K&N filters, the newer rangers have that exact issue and so does the focus, probably a dozen more that I don't recall off the top of my head, not only are we talking about the oil that is on the filter itself but also you are changing the airs dynamics when it enters the MAFS, say the stock air box has a velocity horn in it but the new filter does not, that will have slowed the air down and made it more turbulent, the ECU has preset air flow charts for the MAFS readings and changing the way the air flows will mess with the ECU fuel map.
also don't forget that since the K&N filters at best filter less then half as well as a paper filter there is the issue of debris collecting within the intake track and again causing issues with air flow,
it's a well known fact, how does a filter lose restriction while keeping the same surface area?
here is a link to a report on the different filters,
http://home.stny.rr.com/jbplock/ISO5011/...
K&N knows about the issues, I am on a couple of forums and people have called K&N about it, and it has been remarked that the issues was fixed by replacing the stock airbox, no manufacturer put doubts about their product out there on the package, and on some cars it's no real issue, especially in areas that have low dust levels,
not really interested in arguing about it, just thought I would put in a view that was not expressed before
Hey EmissionWiz: COOL YOUR JETS. I too agree with Toyotaed, he is very, very right.
What is it with you? Do you think that God came down & has now personally granted you supreme knowledge? ...Jeeeeeeeeez...Guys like you with an ASE cert think that you know it ALL. Whuff. You pass a few tests and have a few years under your belt and all of a sudden you are single-handedly reinventing the wheel, for no apparent reason, without success. Duh. You are supposed to be HELPING PEOPLE here, not FLAMING the helpers. If you put more of you so-called vast knowledge to work for you, you should be a millionaire on this board. But, since you only have three (3) chats, and nothing worth a poo on any of them, I can see why...Your assistance posts like "pull the door panel & change the speakers" just STINKS to high heaven. You were a LOT OF HELP to that poor kid....NOT!
You silly, silly fool.
You should be REMOVED from this board because you are a stinking PRIMA-DONNA.
I'll bet your co-workers hate you at your dealership, too.
I agree with toyota ed i have also seen the problem with the k&n filters and also in our shop people bring in there cars with the KN and we tell them there is an up charge to service the filter. and they say that they will take care of it . and the next time there in it still hasnt been changed or there in with a driveabilty problem.( K&N not good for the average JOE)
i have seen a couple of problems with the k&n
the first was the customer never oiled the filter after cleaning. then i could see it being less efective than paper.
second issue was lack of maintence (not cleaning the filter)
i was just fighting a 98 chevy with driveability problems and found this about a factor service bulliton from gm on aftermarket oiled air filters
Because I see this situation every week. I am a Toyota/Scion Service Manager.
On Toyota engines, seeing a P-0171 is a fuel trim code; lean condition...It would be rare to see what you are mentioning above, sorry....
Re: K & N: The K & N users think that the K & N is just soooooooo good. But, it is not the FILTER that causes the problem; it is the OIL that they overload it with to trap the dirt. The oil is then sucked into the intake tube, and what is next in line? The mass air flow sensor. The oil then congreates on the sensor wires, and throws a P0171 fuel trim code because the wires are no longer reading the proper air velocity. I clean the sensor, reset the light, do a drive cycle & then watch the fuel trims walk right back to specs on the scan tool. Hope this clarifys my point..
Ed
I have stepped off of this thread, but, I guess that I am going to have to step back on....
First, "ASE supertech" if you really are one, nobody asked for your inane and uncalled for commentary. Where are YOUR posts and solutions that Em Wiz & myself have garnered? You have NO CREDS. So, keep your 2 cents to yourself, tovarich. We do NOT need pizdas such as you here. Keep it up, and I will get Lauren to kick your dupa off of this board. DA?
Virgils: WOW. What a cool link. For those dudes to go thru all of that govno & $$$ to determine the functionality of a filter is awesome. BUT, that being said, I have a 540 Scott Shafiroff Camaro and a twin turbo Supra, both protected by K & N, no issues. But, again, we are not talking about 2 "normal" cars here, these babies are the fastest cars in town, period. I would put a K & N in my Lotus Elite if I could get one to fit. The isssue that I was discussing with the Wiz was the P-0171, and is quite common to my Corolla/Matrix products...And, my experience with K & N owners is lack of proper maintenance/usage of the K & N product, re-read above. I ain't slapping K & N, just the zatnizdas that think that "a little oil is good, a LOT must be better"...
The issue does exist with Ford? Interesting. Hey, EmWiz, look into this for me, can ya? Lets do some snooping here. We owe it to ourselves. Good post, Virgils. Keep me & EmWiz up on this.
Come to think of it, Toy cars with the P-0171... the MAFs ARE closer to the air box. Hmmmm. Maybe we are on to something here... Agreed, great stuff here.